1. Field of the Invention
This invention relates to gas lift systems for the production of fluid from oil, gas, or water wells and, more particularly, to a gas lift system for the production of fluid from oil, gas, or water wells using a gas displacement chamber.
2. Description of Related Art
The present invention is directed to well tools for oil and gas wells for lifting fluids from oil and gas wells. High pressure injection gas has been used to produce well fluids from oil and gas wells for many years utilizing either continuous flowing or intermittent flowing gas lift systems. Both gas lift systems are well known to the petroleum industry. Chamber gas lift, with or without a single reverse flow check valve in the bottom, has also been used in various forms, for intermittent gas lift production and for providing a deeper lift point of injection in both intermittent gas lift or continuous gas lift wells with long producing zones and/or multiple zones. Other previous chamber lift systems utilizing two-stage chamber lift produced fluid in two intermittent phases or slugs, first from the lower chamber into the production conduit above an upper reverse flow check, and then producing the slug of fluid to the surface intermittently have been used. The lower chamber could be vented into a low pressure conduit between the next simultaneous lift cycle. Early examples were “Camp Pump” (George Camp) and the Teledyne Merla “ACV” Automatic Chamber Vent devices in the 1970-1980's.
The use of wire line retrievable gas lift valves in side pocket gas lift mandrels has been well known in the industry for many years. Coiled tubing service rigs can now perform most of the same operations. The use of side pocket mandrels in chamber gas lift wells has also been common for many years; however, such mandrels and corresponding valves have been limited to two pocket seal areas, separate from the latch profile and any latch debris seal area. Prior art includes an earlier pilot valve with two pocket seals which did provide a method of injecting lift gas into the chamber and then venting residual lift gas from the chamber back into the fluid production conduit after the fluid slug had cleared the tubing at the surface and pressure decreased between injection cycles. The valve had a very small and complicated vent passageway which traveled through the valve main and pilot sections and discharged above the upper pocket seal and back into the interior area of the mandrel.
Three-seal pocket wire line retrievable valve mechanisms have been used in subsurface safety valve systems for oil and gas wells; however, these valves and mandrels have been limited to a single passageway for shutting off a flow conduit in case of emergencies. The area between upper two seal areas provides only an inlet for an actuating signal from a separate surface conduit to the valve controlling a single flow passageway.